1. Field of the Invention
The present invention relates to a method for producing a spot-size convertor.
2. Description of the Related Art
U.S. Pat. No. 6,229,947 discloses a semiconductor optical device and a spot-size convertor of a monolithically integrated tapered rib waveguide type.
The spot-size convertor disclosed in U.S. Pat. No. 6,229,947 includes a top waveguide and a bottom waveguide. The top waveguide and the bottom waveguide are produced by etching of a stacked semiconductor layer. The stacked semiconductor layer includes an upper cladding layer, a first core layer, a separation layer, and a second core layer. The first core layer is included in the top waveguide. The second core layer is included in the bottom waveguide. The separation layer is provided between the first core layer and the second core layer. The spot-size convertor has a region where light transfers from the top waveguide to the bottom waveguide.